The present invention deals with a device for generating a water curtain (or a liquid sheet) for confining an environment where different types of pollutions, acoustic, thermal, gaseous and particle, are present and may occur simultaneously or independently, or for a cooling tower. This device can deal with one of the above-mentioned pollutions or all four. The confinement of objects which are the source of these pollutions is a problem frequently encountered in an industrial context but also in a public context. The invention can be used for the confinement of all types of machines emitting such pollutions, such as boilers, motors, pumps, turbines, etc.
In numerous industries, the safety standards concerning noise pollution limit the levels of noise in zones which are populated by humans. The solutions known to limit noise travelling include the installation of acoustic screens or panels around the noisy environment.
Regarding air pollution, regulations require the positioning of screens around the sensitive zone, limiting the spread of gas, liquid and solid pollution toward the environment to be protected. In other cases, for regulatory or technical reasons, it is sometimes necessary to evacuate some of the heat generated by equipment. In general, it is normal to use materials confining noise pollution in the form of solid panels containing absorbent layers (layers that have different characteristics) in order to disrupt the sound waves. These signs also allow the confinement of gaseous, particle and thermal pollutions, as described in document U.S. Pat. No. 7,604,695 B2. Nevertheless, the presence of openings in the latter affects the quality of acoustic and thermal isolation; their number and surface are often limited. The use of these panels to obtain a closed area causes difficulty in accessing said areas, for example to service or maintain the confined equipment.
There are also gas and chemical depollution systems by a simple liquid wall, but they do not go together with an acoustic element. Document FR 2 641 201 discloses a double water curtain for confining an area of space susceptible to air pollution, but that only creates a simple curtain without a closed outline and does not ensure continuity of the liquid sheet proposed by the present invention.
The invention refers to the reception of one or two liquid sheets allowing the confinement of the polluted environment to be maintained, without provoking or moving the pollutions towards the environment to be protected.
There are high-pressure water jet receptors for cutting sheet metal. An example of this system is given in document U.S. Pat. No. 3,730,040. This device is designed to absorb the energy of the water in order to reduce the noise caused. However, the application and the characteristics of the liquid and system are not in the same context as the present invention.
A water cooling receptor, such as that described in document U.S. Pat. No. 4,130,613, allows the collection of the water falling from a cooling tower and to prevent noise from the fall spreading outward. However, the scope of the application and the intrinsic design of the system are not the same as in the present invention.
A reception device for free-falling liquid described in document U.S. Pat. No. 4,385,010, allows the reduction or elimination of the vertical speed of the liquid, but does not allow noise pollution to be limited.
There are active systems for reducing noise, such as the device described in document U.S. Pat. No. 5,394,376, which includes noise sensors, signal processing system and emission systems for phase shift pressure oscillations with the intention of reducing or cancelling vibrations caused by the flow of the liquid. Other systems include making an opposing noise to cancel the noise created by the liquid. However, the technologies reducing active noise are generally complex and expensive.